196 A SEARCH IN SECRET EGYPT
of the motion of the earth, the axis of our globe points successively at different Pole Stars. That really means that our own sun travels around a parent sun. This almost imperceptible backward movement of the Equinox—so vast in number of years and so slow in actual motion—also changes the positions of the rising and setting of certain stars in relation to certain constellations. We know, by means of the measured average motion of those stars, how many tens of thousands of years have elapsed since their first position. This interval of time is called the Great Precession, or else "the precession of the equinoxes." For the intersection of the equator with the ecliptic, marking the spring equinox, is slowly displaced in the heavens owing to this precession.
Put in another way, it means that the stars are slipping back in an opposite direction to the order of the twelve signs of the zodiac, a minute fraction of space each year. This grand movement of the heavens, this slow shifting of our universe, forms a cosmic clock with the entire sky as its dial, from which we may read backwards and forwards and by which we may note the revolutions of the globes for thousands of years.
By an examination of an ancient map of the heavens it is possible for an astronomer to deduce the period when the map was made. Those who probe the distant past can sometimes find clues of immense importance in such a map. When the learned men whom Napoleon brought with him to Egypt discovered this zodiac at Denderah, .they became enthusiastic over it, believing that it would provide them with a key to the age of Egypt's civilization. For the Denderah zodiac placed the spring equinox far from its present position. When, much later, it was discovered that the temple had only been built in Graxo-Roman times and that the zodiac had been mingled with a Greek one, the whole thing was thrust aside and henceforth ignored.
The suggestion that this zodiac is entirely Greek is erroneous. Is it thought that the Egyptians, therefore, had no zodiac, of their own? Did the priesthood study astrology and astronomy for countless years without having a zodiac, before the first Greek boat touched the long line of Egypt's low sandy shore, a map of the twelve constellations of the sky, to guide them? How did this priesthood, which venerated astrology so much as to make it a part of their religion, practise their system without a zodiac? No, if there was any branch of knowledge upon